DWP commissioners proceed with plans to dump the utility's interest in a coal-burning plant in Arizona and convert another plant in Utah to natural gas.

The coal-powered Intermountain Power Project in Delta, Utah, is a large… (Los Angeles Department…)

Los Angeles officials are speeding up plans to end the city's reliance on coal-powered energy, a move that could help Mayor Antonio Villaraigosa's drive to burnish his legacy as an environmental leader.

On Tuesday, commissioners at the Department of Water and Power moved forward with plans to dump the utility's interest in a coal-burning plant in Arizona and convert another one in Utah to natural gas. The plants provide nearly 40% of the city's energy.

The changes, coupled with new commitments to renewable power, would make the city coal-free by 2025, utility officials said.

That is two years earlier than a state-imposed deadline that requires the utility to be coal-free by 2027, when its contract with Utah's Intermountain Power Project is up. But it is five years later than a target set by Villaraigosa at the outset of his second and final term, when he pledged to drop coal completely by 2020. Shakeups in DWP leadership, the failure of several renewable energy proposals and the grip of long-term contracts with out-of-state power producers have kept the mayor's goal out of reach.

Still, Villaraigosa declared victory Tuesday, calling the coal divestment plan "game-changing" even though it won't meet the timeline he set. "I believe the only way to get the goal is to set aggressive timetables," he said. "Climbing mountains that have never been climbed before [isn't] easy."

Villaraigosa's office issued a news release with a congratulatory quote from former President Bill Clinton and announced plans for a Friday news conference celebrating the measures with environmentalists and former Vice President Al Gore, who has made climate change a priority.

The Sierra Club and other environmental advocates have been pushing the city for years to speed its divestment from coal, which is cheaper than green alternatives but which pollutes the air with toxic metals and greenhouse gas emissions.

The DWP is in negotiations to sell its 21% share of the Navajo Generating Station in Page, Ariz., which will allow the utility to stop receiving power from the plant by 2015, four years before its current contract is up. Getting free of coal at the Intermountain Power Project in Delta, Utah, is more complicated because the DWP does not own the plant and is bound by contract to buy its power through 2027.

On Tuesday the Board of Water and Power Commissioners approved an amendment to its contract with Intermountain Power to allow the plant to transform its power supply to cleaner natural gas. The gas plant would be smaller than the current one, freeing up space along existing transmission lines for new renewable energy projects.

Both of the contract changes will require City Council approval.

Environmentalists cheered the proposed changes, which they said would make L.A. the largest city in the nation to go coal-free.

"There's no utility in the country going faster and further," said Evan Gillespie, of the Sierra Club. He said that eliminating the city's consumption of coal-fired energy from the two plants would be equivalent to taking 2 million cars off the road.

But questions remained about how much the plan would cost. The utility's comissioners did not discuss how the changes would affect rates for customers, which neighborhood council member Jack Humphreville said was troubling. "I haven't seen any numbers; there hasn't been any outreach," he said.

A report released by the utility last year estimated that ending coal-power consumption at the Utah plant four years ahead of schedule would cost nearly $1 billion over four years in higher replacement fuel costs and other expenditures.

DWP General Manager Ron Nichols said the exact costs will be determined over time. But he said that getting out of contracts that require the city to buy coal is a smart move, given new federal regulations that will require many coal plants to make costly improvements to reduce emissions in the future.

"It's the least risky approach forward for us," he said.

Nichols said that converting the Intermountain Power Plant in Utah to gas may cost around $1 billion, which would probably be shared among the utilities that buy power from the plant. Building a new power plant that would have the same capabilities would cost more than $11 billion, he said.

The DWP's ratepayer advocate said he supported the acceleration of the phase-out of coal, although he wants to see more details about how the city will provide reliable power, and at what cost.